In the field of concrete forming, several structures are available for supporting panels which define floor areas onto which concrete is poured. In situations where there is sufficient area surrounding the building being constructed and the construction is above ground, a large scale concrete forming structure of the type disclosed in Avery, U.S. Pat. No. 3,787,020 issued Jan. 22, 1974 is advantageously used. Such structures can be rolled out from underneath a poured set floor, raised by crane and placed on the freshly set floor to support panels defining the next floor. Such concrete forming structure is made of aluminum beams and truss components having hinged screw jacks associated with the lower portion of the structure to facilitate levelling of the forming structure prior to pouring and removal of the structure from under the set concrete floor.
Other types of aluminum structures, which are used in the concrete forming industry, are, for example, disclosed in Dashew, U.S. Pat. No. 3,966,164 issued June 29, 1976. The patent discloses an adjustable truss support, wherein a bolted truss has vertical column members forming components of the trusses. Lower column members may be inserted in the trusses to provide supports having height adjustment and force determination so as to be able to support the truss loads. The truss construction is not entirely of aluminum and, in particular, the column members are made of steel. The choice of steel is because of its strength characteristics compared to aluminum. This results in a structure having mixed materials with some chance of galvanic corrosion.
Van Meter, U.S. Pat. No. 4,036,466 issued July 19, 1977, discloses concrete shoring structure which may be moved about by use of a crane. The structure comprises corner posts spaced in quadrilateral relationship, supporting pairs of stringers along opposed sides of the quadrilateral so formed. In the structure, a number of pins are used to secure cross-braces in two different directions where the spacing between the corner posts can be easily changed. Arrangements are made using a shackle on each post to lift the structure and telescopically engaged staffs are secured within the corner posts by pins for adjusting the height of the structure. However, the structure has limited effectiveness and, in any event, requires considerable assembly at the site. The pins in most instances are welded to the supporting structure, so that if they are damaged or broken they cannot be easily replaced or repaired in the field.
Cody, U.S. Pat. No. 4,106,156 issued Aug. 15, 1978, discloses an adjustable concrete shoring apparatus. A truss-like structure has a plurality of diagonal struts extending between pairs of back-to-back channels which form upper and lower cords of the truss. The adjustability in the Cody structure comes as a consequence of a series of holes through which bolts may be passed in the plurality of truss forming locations, by which the spacing between upper and lower cords can be adjusted, but also by which the load capacity of the truss is affected. The Cody structure is one which can be adjusted in the field, but in order for it to be manupilated by hand, it must be totally disassembled.
In situations where sub-basements, parking garage floors below ground level, and smaller scale installations where cranes of suitable capacity are not readily usable, a lightweight shoring frame is desirable for supporting structure onto which concrete floors may be poured. Such shoring frame supports stringers across which beams, such as those disclosed in U.S. Pat. Nos. 4,144,690 issued Mar. 20, 1979 and 4,156,999 issued June 5, 1979, may be placed. Commonly, such shoring frames have been made from welded steel components which, when damaged in the field, cannot be replaced so that the complete frame must be scrapped or possibly repaired or rewelding.
According to this invention, a frame is provided which may be machanically assembled and disassembled, yet when assembled provides an extremely rigid and high load-bearing capacity frame. The provision of mechanical disassembly provides for repair and/or replacement of components in the frame at the job site without the use of special welding techniques or tools. The legs of the frame are made of aluminum to provide a lightweight structure.